Coloured smoke production

ABSTRACT

The invention provides a process for producing an intense, persistent coloured smoke, wherein a mixture of VOCl3 and a stabilizer, e.g. concentrated sodium hydroxide, which intensifies and prolongs the color of the smoke, is released into the atmosphere. Also, a packaged composition for providing such a smoke, which comprises a sealed frangible container containing a mixture of VOCl3 and a stabilizer of said type.

United States Patent 1 Bachusky et al. June 12, 1973 COLOURED SMOKE PRODUCTION OTHER PUBLICATIONS [76] Inventors g Bachusky 54 gusen Uses and Applications of Chemicals and Related Mateo. 13, Kongston, Ontario, rials, Thomas Gregory, Reinhold Publishing Corp.

" 3153 Fourth Printin 1939 (First Printin 538-539 Quebec, Quebec, both of Canada 8 g [22] Fled: June 7, 1971 A Primary Examiner-Benjamin A. Borchelt [2]] APPL 150,729 Assistant Examiner-Harold Tudor Attorney-Edward J. Kelly [52] US. Cl 102/90, 149/102Q252/305 51 Int. Cl. F42b 13/44 [571 ABSTRACT [58] Field of Search 252/305; 102/90; The invention provides a process for producing an in- 149/ 102, 31 tense, persistent coloured smoke, wherein a mixture of VOCl and a stabilizer, e.g. concentrated sodium hy- References Ciled droxide, which intensities and prolongs the color of the UNITED STATES PATENTS smoke, is released into the atmosphere. Also, a pack- 3,4o2,129 9/1968 Tatyrek 252/305 aged Pmviding Such Smke, which 3 297 503 9 7 H ff a etal comprises a sealed frangible container containing a 2,175,790 10/1939 Nutley mixture of VOCl and a stabilizer of said type. 2,733,217 1/1956 Woyski et al. 2,995,526 8/1961 Dement 149/74 4 Claims, N0 Drawings COLOURED SMOKE PRODUCTION The invention described herein may be manufactured, used, and licensed by or for the Government for governmental purposes without the payment to me of any royalty thereon.

This invention relates to a process for the production of coloured smoke and to the packaged composition for producing such smoke.

Coloured smoke is used in many Military applications as, for example, marking bomb strikes, impact points of artillery, air to ground signalling and the like. Usually, coloured smoke as used in Military applications, must be produced instanteously, that is to say, at essentially explosive speed, if it is to be satisfactory. Known techniques for producing coloured smoke include explosive dissemination of various complex mixtures and imploding sheet explosives on dye mixtures to form a coloured cloud. For example, white smoke clouds can be obtained by explosively disseminating titanimum tetrachloride. White smoke clouds suffer from a visibility limitaiton and it is desirable to produce a coloured smoke cloud that may be seen readily against snow or ice covered terrain.

A further limitation to coloured smoke clouds as presently produced, is their diffuse nature in that the clouds produced are thin and disseminate very quickly. Further, clouds produced by the imploding dye technique where dyes are encased in an explosive sheet, present a particular danger when used with low flying aircraft. In some instances, one aircraft following another has flown into the explosive charge or, if there should be a misfire, the explosive charge may be left in the path of the following aircraft.

lt presently is known that vanadium oxytrichloride (VOCl may be released into the atmosphere to produce an orange coloured smoke cloud. However, the

cloud produced is of very short duration (1 k to 10 seconds) and, because of this, VOCl has not been used for this purpose.

The present invention utilizes vanadium oxytrichloride (VOCl in combination with a stabilizing chemical which intensifies the colour of the cloud produced and produces an orange coloured cloud that will retain its colour until the cloud is normally dispersed by the atmosphere.

Examples of stabilizing chemicals that may be used with vanadium oxytrichloride (VOCl are vanadium pentoxide (V or a concentrated solution of sodium hydroxide (NaOH).

in the case where vanadium pentoxide (V,O is used, the orange colour produced by the release of vanadium oxytrichloride to the atmosphere is intensified and persists because of an excess of vanadium pentoxide in the cloud. Without the excess of vanadium pentoxide in the cloud, there is a secondary reaction which causes the cloud rapidly to turn from orange to white.

In the mixture using sodium hydroxide (NaOH), the secondary reaction is prevented because the base uses up the HCl of the primary reaction.

Vanadium oxytrichloride (VOCl is a liquid which will fume under normal atmospheric temperature and pressure conditions to produce an orange cloud of very short duration. Care must be taken in handling VOCl owing to the fact that it will react quickly with many common organic materials and, therefore, must be stored in a container formed from either teflon or a metal such as aluminum, carbon steel, and stainless steel.

Vanadium pentoxide (V 0 is a solid and no difficulty is encountered in storing this material.

Sodium hydroxide solution (NaOH) is a liquid and may be readily stored in a glass or plastic container.

Usually, VOCl and V 0 may be mixed together and sealed in a suitable frangible container using standard procedures. For example, an inert nitrogen atmosphere may be created and VOCl and V 0 may be mixed together in such an atmosphere with no reaction. When stored in a suitable container, the mixture may be handled in ordinary fashion and may be disseminated using a conventional procedure. For example, an explosive charge (a '1 O-gauge shotgun shell) may be tired to create pressure which will rupture the container. When the container is ruptured, the pressure will then drive the chemical mixture into the atmosphere where there will immediately be produced an orange cloud which will last for a substantial period of time as compared with the prior art.

While the proportions of the ingredients in the mixture may be varied it has been found that the preferred mixture uses to per cent VOCl and 30 to 10 per cent V 0 In the case of NaOl-l, the preferred mixture is 50 to 90 per cent by weight VOCl and 10 to 50 per cent by weight NaOl-I.

Vanadium oxytrichloride (VOCl and a concentrated solution of sodium hydroxide (NaOH) may not be pre-mixed since the mixture of these two chemicals will result in an immediate violent reaction to produce a coloured orange cloud. It is necessary, therefore, that the two liquids be packaged separately and that they be combined only when it is desired to produce the orange coloured smoke cloud. While a number of methods for accomplishing this can be used, the well known technique of disseminating liquids from an artillery shell on impact may be used. Such methods are presently well known for the distribution of gases or insecticides and it would simply require that the separate containers of liquid be ruptured when the shell or other delivery vehicle has reached its desired location and so that the separated chemicals would be forcibly and quickly combined as desired to produce the coloured orange cloud.

It will be seen, therefore, that there has been provided a process for producing orange coloured smoke wherein there is no fire hazards since no heat or flame is necessary to produce the smoke and wherein the orange coloured smoke cloud will persist until the cloud is normally dispersed by the atmosphere.

We wish it to be understood that we do not desire to be limited to the exact details of construction shown and described, for obvious modifications will occur to a person skilled in the art.

We claim:

1. A packaged composition for producing an intense orange coloured smoke cloud capable of existing for a substantial period of time comprising: a sealed frangible container containing a mixture of VOCl and a basic substance as a stabilizing chemical, which neutralizes the HCl produced by the reaction of VOCl with atmospheric moisture, thereby reducing any secondary reaction in the smoke cloud causing the cloud to change from orange to white in colour.

2. The packaged container of claim 1, wherein the stabilizing chemical is V 0 3. The packaged container of claim 2, wherein the percentage of VOCl is 70 to 90 per cent and the percentage of V 0 is 10 to 30 per cent.

4. The packaged container of claim 1, wherein the stabilizing chemical is NaOH.

* i III 

2. The packaged container of claim 1, wherein the stabilizing chemical is V2O5.
 3. The packaged container of claim 2, wherein the percentage of VOCl3 is 70 to 90 per cent and the percentage of V2O5 is 10 to 30 per cent.
 4. The packaged container of claim 1, wherein the stabilizing chemical is NaOH. 